Adding to what Mark Williamson said, if you're using the "tell" syntax
 for the address, meaning    user at node     then LISTSERV will see it
 as <user@localnode> with a name of "At Node".  I'm just grasping at
 straws here, but make sure to use the command syntax,
 
    add list-name user@node Full Name
 
 and it should work fine.
 
 -jj